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-rw-r--r--drivers/xen/xen-pciback/xenbus.c2
-rw-r--r--drivers/xen/xenbus/xenbus_client.c8
-rw-r--r--drivers/xen/xenbus/xenbus_probe.c1
-rw-r--r--drivers/xen/xenbus/xenbus_probe.h2
-rw-r--r--drivers/xen/xenbus/xenbus_probe_backend.c7
-rw-r--r--drivers/xen/xenbus/xenbus_xs.c38
6 files changed, 43 insertions, 15 deletions
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 48196347f2f9..12497a2140c2 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -691,7 +691,7 @@ static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
/* watch the backend node for backend configuration information */
err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
- xen_pcibk_be_watch);
+ NULL, xen_pcibk_be_watch);
if (err)
goto out;
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 266f446ba331..8bbd887ca422 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -114,18 +114,22 @@ EXPORT_SYMBOL_GPL(xenbus_strstate);
*/
int xenbus_watch_path(struct xenbus_device *dev, const char *path,
struct xenbus_watch *watch,
+ bool (*will_handle)(struct xenbus_watch *,
+ const char **, unsigned int),
void (*callback)(struct xenbus_watch *,
const char **, unsigned int))
{
int err;
watch->node = path;
+ watch->will_handle = will_handle;
watch->callback = callback;
err = register_xenbus_watch(watch);
if (err) {
watch->node = NULL;
+ watch->will_handle = NULL;
watch->callback = NULL;
xenbus_dev_fatal(dev, err, "adding watch on %s", path);
}
@@ -152,6 +156,8 @@ EXPORT_SYMBOL_GPL(xenbus_watch_path);
*/
int xenbus_watch_pathfmt(struct xenbus_device *dev,
struct xenbus_watch *watch,
+ bool (*will_handle)(struct xenbus_watch *,
+ const char **, unsigned int),
void (*callback)(struct xenbus_watch *,
const char **, unsigned int),
const char *pathfmt, ...)
@@ -168,7 +174,7 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev,
xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
return -ENOMEM;
}
- err = xenbus_watch_path(dev, path, watch, callback);
+ err = xenbus_watch_path(dev, path, watch, will_handle, callback);
if (err)
kfree(path);
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index c2d447687e33..ba7590d75985 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -137,6 +137,7 @@ static int watch_otherend(struct xenbus_device *dev)
container_of(dev->dev.bus, struct xen_bus_type, bus);
return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
+ bus->otherend_will_handle,
bus->otherend_changed,
"%s/%s", dev->otherend, "state");
}
diff --git a/drivers/xen/xenbus/xenbus_probe.h b/drivers/xen/xenbus/xenbus_probe.h
index c9ec7ca1f7ab..2c394c6ba605 100644
--- a/drivers/xen/xenbus/xenbus_probe.h
+++ b/drivers/xen/xenbus/xenbus_probe.h
@@ -42,6 +42,8 @@ struct xen_bus_type {
int (*get_bus_id)(char bus_id[XEN_BUS_ID_SIZE], const char *nodename);
int (*probe)(struct xen_bus_type *bus, const char *type,
const char *dir);
+ bool (*otherend_will_handle)(struct xenbus_watch *watch,
+ const char **vec, unsigned int len);
void (*otherend_changed)(struct xenbus_watch *watch, const char **vec,
unsigned int len);
struct bus_type bus;
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index 04f7f85a5edf..597c0b038454 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -181,6 +181,12 @@ static int xenbus_probe_backend(struct xen_bus_type *bus, const char *type,
return err;
}
+static bool frontend_will_handle(struct xenbus_watch *watch,
+ const char **vec, unsigned int len)
+{
+ return watch->nr_pending == 0;
+}
+
static void frontend_changed(struct xenbus_watch *watch,
const char **vec, unsigned int len)
{
@@ -192,6 +198,7 @@ static struct xen_bus_type xenbus_backend = {
.levels = 3, /* backend/type/<frontend>/<id> */
.get_bus_id = backend_bus_id,
.probe = xenbus_probe_backend,
+ .otherend_will_handle = frontend_will_handle,
.otherend_changed = frontend_changed,
.bus = {
.name = "xen-backend",
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index ce65591b4168..d98d88fae58a 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -701,6 +701,8 @@ int register_xenbus_watch(struct xenbus_watch *watch)
sprintf(token, "%lX", (long)watch);
+ watch->nr_pending = 0;
+
down_read(&xs_state.watch_mutex);
spin_lock(&watches_lock);
@@ -750,12 +752,15 @@ void unregister_xenbus_watch(struct xenbus_watch *watch)
/* Cancel pending watch events. */
spin_lock(&watch_events_lock);
- list_for_each_entry_safe(msg, tmp, &watch_events, list) {
- if (msg->u.watch.handle != watch)
- continue;
- list_del(&msg->list);
- kfree(msg->u.watch.vec);
- kfree(msg);
+ if (watch->nr_pending) {
+ list_for_each_entry_safe(msg, tmp, &watch_events, list) {
+ if (msg->u.watch.handle != watch)
+ continue;
+ list_del(&msg->list);
+ kfree(msg->u.watch.vec);
+ kfree(msg);
+ }
+ watch->nr_pending = 0;
}
spin_unlock(&watch_events_lock);
@@ -802,7 +807,6 @@ void xs_suspend_cancel(void)
static int xenwatch_thread(void *unused)
{
- struct list_head *ent;
struct xs_stored_msg *msg;
for (;;) {
@@ -815,13 +819,15 @@ static int xenwatch_thread(void *unused)
mutex_lock(&xenwatch_mutex);
spin_lock(&watch_events_lock);
- ent = watch_events.next;
- if (ent != &watch_events)
- list_del(ent);
+ msg = list_first_entry_or_null(&watch_events,
+ struct xs_stored_msg, list);
+ if (msg) {
+ list_del(&msg->list);
+ msg->u.watch.handle->nr_pending--;
+ }
spin_unlock(&watch_events_lock);
- if (ent != &watch_events) {
- msg = list_entry(ent, struct xs_stored_msg, list);
+ if (msg) {
msg->u.watch.handle->callback(
msg->u.watch.handle,
(const char **)msg->u.watch.vec,
@@ -903,9 +909,15 @@ static int process_msg(void)
spin_lock(&watches_lock);
msg->u.watch.handle = find_watch(
msg->u.watch.vec[XS_WATCH_TOKEN]);
- if (msg->u.watch.handle != NULL) {
+ if (msg->u.watch.handle != NULL &&
+ (!msg->u.watch.handle->will_handle ||
+ msg->u.watch.handle->will_handle(
+ msg->u.watch.handle,
+ (const char **)msg->u.watch.vec,
+ msg->u.watch.vec_size))) {
spin_lock(&watch_events_lock);
list_add_tail(&msg->list, &watch_events);
+ msg->u.watch.handle->nr_pending++;
wake_up(&watch_events_waitq);
spin_unlock(&watch_events_lock);
} else {
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-08 12:46:40 +0000